mgagit: Add a repo group for infrastructure stuff.
This is slightly recursive as this is where the definitions are kept, but
I'll add a readme to the git repo to make sure no-one actually adds definitions
in this tree (although a pre-receive hook would be better to really ban it)

mgagit: Update to git_multimail.py e12918c100.
This is from https://github.com/mhagger/git-multimail
I've reapplied my changes which avoid some unnecessary error messages when the summary
email address is not configured (used for i18n mails).
The notable change is to synthesise dates in emails to hopefully fix ordering in
email clients (i.e. with multi-commit pushes).

mgagit: Send a second email about any i18n changes to the i18n-reports ML.
After sending the original email, we send a second email to i18n-reports
detailing any i18n changes.
The method of determining if any changes affect i18n is to look for a
folder (or folders) called '.tx' in the tree. If such folders exist,
then any changes in their parent folders are considered to be relevent
for i18n.

mgagit: Don't report any error message when no change email address configured.
When we will send to the i18n-reports ML info about i18n related changes we
will omit the overall summary mail (it's too complext to produce a summary
of only i18n changes) and thus we need to squash this error message which
will not be nice for those pushing changes.

git: Make git pulls silent.
This avoids the 'Already up to date.' messages and mirrors
what the subversion module does.
(fixes previous commit which put the -q in the wrong place
and had a comment about the lack of -q)

Add a new system to ensure our git repos are mirrored properly.
This is a simple python daemon that I wrote which can be 'pinged' and told
to update (or freshly clone) given git repos.
Deploy this script on alamut (not started automatically yet)

mgagit: Attempt to write out a last-modified file for cgit.
This means the Last Modified column in cgit will show the date of the last commit
not the date of the last push (which can be completely unrelated, especially when
doing rebases or forced pushes and fixups etc.)
Note: If we stop using rsync for replication then this can be removed and replaced
with a different hook on the receiving side.